Progressive Lean: Straighten and See Part 6: Takt Time 1
[Editior's note: I edited this post after publishing it but not substantially. It reads the same but the flow is a bit different.]
Now, after we've discussed the purpose and use of the Hourly Charts, is a good time to talk about Takt Time.
I confess that I didn't really understand the whole idea of takt time until I started using hourly charts. The definition of takt time in all the lean literature confused me: takt time is total customer demand divided by the time available to meet that demand.
I have mostly worked in job shop environments. In many of the plants I've worked, products were made in one step...extrusion, metal stamping, roll forming, plastics and rubber molding, for example. These places are always producing in a way to correlate production rates with customer demand, I thought. What's the big deal?
Well, job shop or not, every place I've ever worked has a production rate associated with each product on each machine. This rate is typically used to figure efficiency. It's also used for scheduling: If a given product runs at 50 per hour and has a setup time of four hours, I know I'll need 24 hours to run the 1000 parts I need. So..assuming the part is made on one machine, takt time is the same (more or less) as rate . Once I had that figured out, takt time was easier to think about.
The "run at takt" idea is, generally speaking, easy enough to get across in "one step" processes. The idea really comes into its own when a product isn't made in one step. When a product is made on a line or in a cell, it's vital to think of the takt time or rate of the whole line or cell. That means that the rate of individual machines or steps within the cell might need to be adjusted to conform to the overall takt time. for example, if my rate is 100 per hour and your rate is 50 per hour, our rate is 50 per hour and I might as well adjust my rate to yours. This notion really throws cell leaders off at first. (Of course, the other thing we can do is match your rate to mine by adding another person, improving the technology, etc.)
I'm sure I hardly need to point out that the first and most important "rule" that takt time suggests is...you have to produce at takt time (aka: rate). A less obvious corollary of this rule is that you have to produce at takt time...and no more. I've had any number of discussion with supervisors and cell leaders about the issue of producing at faster than takt time or rate. My position is as stated above. The position of many supervisors is: Run as many as you can, as fast as you can. It generally takes a bit of time for those supervisors to see my position because it's so directly counter to the way they've thought about production all their lives.
OK, I have to go pick up the house because our monthly cleaning lady is coming today. I'll talk more about takt time later.
Now, after we've discussed the purpose and use of the Hourly Charts, is a good time to talk about Takt Time.
I confess that I didn't really understand the whole idea of takt time until I started using hourly charts. The definition of takt time in all the lean literature confused me: takt time is total customer demand divided by the time available to meet that demand.
I have mostly worked in job shop environments. In many of the plants I've worked, products were made in one step...extrusion, metal stamping, roll forming, plastics and rubber molding, for example. These places are always producing in a way to correlate production rates with customer demand, I thought. What's the big deal?
Well, job shop or not, every place I've ever worked has a production rate associated with each product on each machine. This rate is typically used to figure efficiency. It's also used for scheduling: If a given product runs at 50 per hour and has a setup time of four hours, I know I'll need 24 hours to run the 1000 parts I need. So..assuming the part is made on one machine, takt time is the same (more or less) as rate . Once I had that figured out, takt time was easier to think about.
The "run at takt" idea is, generally speaking, easy enough to get across in "one step" processes. The idea really comes into its own when a product isn't made in one step. When a product is made on a line or in a cell, it's vital to think of the takt time or rate of the whole line or cell. That means that the rate of individual machines or steps within the cell might need to be adjusted to conform to the overall takt time. for example, if my rate is 100 per hour and your rate is 50 per hour, our rate is 50 per hour and I might as well adjust my rate to yours. This notion really throws cell leaders off at first. (Of course, the other thing we can do is match your rate to mine by adding another person, improving the technology, etc.)
I'm sure I hardly need to point out that the first and most important "rule" that takt time suggests is...you have to produce at takt time (aka: rate). A less obvious corollary of this rule is that you have to produce at takt time...and no more. I've had any number of discussion with supervisors and cell leaders about the issue of producing at faster than takt time or rate. My position is as stated above. The position of many supervisors is: Run as many as you can, as fast as you can. It generally takes a bit of time for those supervisors to see my position because it's so directly counter to the way they've thought about production all their lives.
OK, I have to go pick up the house because our monthly cleaning lady is coming today. I'll talk more about takt time later.
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